Here is the full list of all 37 Philosophical Jigsaw - there are The Zen Koans achievements.
Solve a 25 pieces jigsaw
Solve a 64 pieces jigsaw
Solve a 144 pieces jigsaw
Solve a 324 pieces jigsaw
Solve all jigsaws on any difficulty
Solve all jigsaws of "The Flag" on any difficulty
Solve all jigsaws of "Heaven and Hell" on any difficulty
Solve all jigsaws of "Happy Fish" on any difficulty
Solve all jigsaws of "The Clap" on any difficulty
Solve all jigsaws of "The Taste of Melon" on any difficulty
Solve the first puzzle of "The Flag" on any difficulty
Solve the second puzzle of "The Flag" on any difficulty
Solve the third puzzle of "The Flag" on any difficulty
Solve the first puzzle of "Heaven and Hell" on any difficulty
Solve the second puzzle of "Heaven and Hell" on any difficulty
Solve the third puzzle of "Heaven and Hell" on any difficulty
Solve the fourth puzzle of "Heaven and Hell" on any difficulty
Solve the fifth puzzle of "Heaven and Hell" on any difficulty
Solve the first puzzle of "Happy Fish" on any difficulty
Solve the second puzzle of "Happy Fish" on any difficulty
Solve the third puzzle of "Happy Fish" on any difficulty
Solve the fourth puzzle of "Happy Fish" on any difficulty
Solve the fifth puzzle of "Happy Fish" on any difficulty
Solve the first puzzle of "The Clap" on any difficulty
Solve the second puzzle of "The Clap" on any difficulty
Solve the first puzzle of "The Taste of Melon" on any difficulty
Solve the second puzzle of "The Taste of Melon" on any difficulty
Solve the third puzzle of "The Taste of Melon" on any difficulty
Solve the fourth puzzle of "The Taste of Melon" on any difficulty
Go to the garden
Watch a Koan Cutscene again.
Find a hidden flag
Find a hidden torch
Find a happy fish
Play the hidden gong
Find a hidden melon
Get the candle achievement